Regenerator seal

ABSTRACT

A rotary regenerator of the drum-matrix-type. The regenerator matrix is located and supported by two parallel rollers engaging the matrix rims at the inner or hot face of the matrix adjacent the bulkhead. The main seals are pivoted adjacent the drive rollers so that they can rotate to align with the matrix notwithstanding expansion and distortion. The angular position of the main seals is determined by aligning rollers engaging the outer or cold face of the matrix and mounted on the main seal frame. These are biased into engagement with the matrix by springs. The particular subject matter is improved structure of the main seals including the frame, roller mounts, cooling provisions, side seals, the secondary seal, and connection of the frame to the regenerator bulkhead.

{mite Hart States atet [54] REGENERATOR SEAL [72] Inventor: Jack P.Hart, l-linsdale, lll.

[73] Assignee: General Motors Corporation, Detroit,

Mich.

[22] Filed: Nov. 25, 1969 [21] App]. No.: 879,729

[52] 11.8. Cl ..165/9, 165/10 [51] Int. Cl ..F28d 19/04 [58] Field ofSearch ..165/9, 10

[56] References Cited UNITED STATES PATENTS 3,384,156 5/1968 Addie..l65/9 X 2,888,248 5/1959 Bubniak et al... .....l65/9 3,298,429 1/1967Bubniak ..l65/9 Feb. l, 1972 Primary ExaminerAlbert W. Davis, Jr.AttarneyPaul Fitzpatrick and Jean L. Carpenter [5 7] ABSTRACT A rotaryregenerator of the drum-matrix-type. The regenerator matrix is locatedand supported by two parallel rollers engaging the matrix rims at theinner or hot face of the matrix adjacent the bulkhead. The main sealsare pivoted adjacent the drive rollers so that they can rotate to alignwith the matrix notwithstanding expansion and distortion. The angularposition of the main seals is determined by aligning rollers engagingthe outer or cold face of the matrix and mounted on the main seal frame.These are biased into engagement with the matrix by springs. Theparticular subject matter is improved structure of the main sealsincluding the frame, roller mounts, cooling provisions, side seals, thesecondary seal, and connection of the frame to the regenerator bulkhead.

3 Claims, 13 Drawing Figures fi lll luu l! y ii 1/,

1/ a; w M #7 If PATENTEU as 11972 3.638.716

SHEET 1 OF 5 A TTO/P/VEY PATENTEU FEB 1 s72 SHEET 2 OF 5 A T TO/QNEYPATENTED FEB H972 3.I638 .7l6

sum .3 or 5 I N VEN TOR A TTOPNEY PATENTEU FEB 1 i972 SHEET 5 OF 5INVENTOR. (/25? #97 E llllll m @T MW YWHHHHM BY M A TTOQNEY REGENERATORSEAL INTRODUCTION My invention relates to regenerators, by which I meanheat exchange devices of the sort in which a heat retaining mass isrotated so as to move alternately through the flow paths of two fluidsso as to absorb heat from the hotter fluid and release it to the cooler.In some respects, it is particularly concerned with a regenerator havinga drum matrix in which flow takes place radially through an annulardrum, and with one suited to a gas turbine type of installation. Theinstallation in a gas turbine involves substantial pressure differencesbetween the two fluids, with attendant problems in supporting the matrixand sealing against leakage from high to low pressure. It also involveshigh temperatures.

The regenerator structure which is the subject of this application isintended for the large regenerative gas turbine engine described inDixon et al. U.S. Pat. No. 3,455,107 for Gas Turbine Engine, July 15,1969. My invention is particularly directed to improvements in a mainseal for such a regenerator disclosed in Addie U.S. Pat. No. 3,384,156for Rotary Regenerator, May 21, I968.

The principal objects of my invention are to improve the reliability anddurability of regenerators; to provide a regenerator structureparticularly adapted for gas turbine service; to provide a regeneratorhaving improved means for supporting and driving the matrix particularlyadapted to horizontal axis matrices of large size; to provide improvedstructure ofa main seal and its supports; to increase sealingefficiency; to reduce manufacturing costs; to facilitate assembly; toimprove resistance to high-temperature gases; to accommodate relativethermal expansion of the parts; and to provide improved lubricating,sealing, and cooling structure for regenerator driving and locatingarrangements.

Various ones or all of these objects may be realized, depending upon theparticular installation and the characteristics of a particular designaccording to my invention, but the seal structure as a whole isparticularly suited to realize the various objects in the locomotiveturbine environment for which it is primarily intended.

The nature of my invention and the advantages thereof will be apparentto those skilled in the art from the succeeding detailed description ofthe preferred embodiment of the invention and the accompanying drawingsthereof.

FIG. I is a somewhat schematic side view, with parts cut away, ofaregenerative gas turbine arrangement.

FIG. 2 is a sectional side view of the upper main seal and adjacentstructures taken on the plane indicated by the line 2-2 in FIG. 3.

FIG. 3 is a sectional view taken on a plane substantially containing theaxes of the matrix and of a set of supporting and driving rollers.

FIG. 4 is a sectional view taken substantially on the plane indicated bythe line 4-4 in FIG. 2.

FIG. 5 is a sectional view taken on the the line 5-5 in FIG. 3.

FIG. 6 is a partial elevation view taken on the plane indicated by theline 6-6 in FIG. 3.

FIG. 7 is a fragmentary sectional view taken on the plane indicated bythe line 7-7 in FIG. 6.

FIG. 8 is a sectional view of the seal housing taken on the planeindicated by the line 3-8 in FIG. 3.

FIG. 9 is a sectional view of bypass seal structure taken on the planeindicated by the line 9-9 in FIG. 2.

FIG. 10 is a partial view of a seal bar taken on the plane indicated bythe line 10-10 in FIG. 2.

FIG. 11 is a cross section ofa main seal support taken on the planesindicated by the line 11-11 in FIG. 12.

FIG. 12 is an elevation view of the main seal support, with parts cutaway and in section.

FIG. 13 is a plan view ofthe same.

Referring first to FIG. 1, which illustrates in a general or schematicway the structure of the regenerator as part of the plane indicated bygas turbine engine referred to above, a gas turbine engine includes aturbine 13 which drives a compressor 14 through a shaft 15 and alsodrives a power output shaft 17. The compressor supplies air to aregenerator 18 which comprises a regenerator case 19 and at least onedrum-shaped regenerator matrix 21; preferably, two matrices rotatingabout the same horizontal axis 22 perpendicular to the axis of theturbine. The matrices are disposed generally side by side with theturbine partially within the matrices and enclosed within the regenerator case. A bulkhead 23 and associated structure divides the interior ofthe regenerator case between a high-pressure chamber 25 into which thecompressor discharges and a lowpressure chamber 26 into which theturbine discharges. Main support and seal assemblies 27 are mounted inthe bulkhead at the places where each drum passes through the bulkheadas it is slowly rotated about the axis 22. Air compressed by thecompressor flows radially inwardly through the forward roughly sector ofthe matrix, through combustion apparatus (not illustrated) and throughturbine 13 to chamber 26 at the rear side of the bulkhead, where theturbine exhaust flows radially outward through the rear sector of thematrix to an exhaust stack 28.

REGENERATOR FIG. 1 illustrates schematically the right-hand regeneratorofthe engine, the left-hand one being simply a mirror image of theright-hand one, and the upper and lower halves of each regenerator beingsubstantially mirror images of each other except for differencesrelating to oil supply and return and to the provision of a power inputinto one of the seal assemblies to rotate the matrix. For background tomy invention, we may consider the regenerator case 19 to comprise aradially outer wall 30 broken by the entrance from the compressor 14 andby the exhaust stack 28; a rear wall 31; and a front wall principallydefined by a cover plate 32, which bolts to the remainder of theregenerator case.

The matrix 21 is supported and located primarily by a drive roller 34mounted within the upper main seal assembly 27 and by an idler roller 35mounted within the lower main seal and support assembly 27, the radiallyinner face of the matrix being in engagement with these rollers tolocate, support, and rotate the matrix. The assemblies 27 also includebiasing or aligning rollers 37 which bear against the radially outerface of the matrix. The matrix is located along its axis of rotation bystructure ofthe main seals at 27, to be described, and by locat ingrollers 38 mounted on the front and rear walls of the case and engagingthe edges ofthe matrix.

The matrix 21 is shown only generally in the drawings as including rims39 which are joined by spacers (not illustrated) and between which islocated porous heat transfer material 41) which may be in the form ofstacked corrugated plates of thin sheet metal. Suitable matrixstructures are shown in considerable detail in Addie and Hart U.S. Pat.Nos. 3,367.405 and 3,435,888 and Hart and Tharp U.S. Pat. No. 3,456,717.For the present, it is sufficient to consider the matrix as being arigid drum of which substantially all except the rim portions is porousto flow in the direction radially of the matrix.

MAIN SEAL ASSEMBLY As previously stated, the function of the mainsupport and seal assemblies 27, in addition to locating and driving thematrix is to prevent, as far as feasible, leakage of the highpressurecompressor discharge air from the chamber 25 into the chamber 26. Eachthus defines a frame through which the matrix passes and which is insealing contact with the inner and outer faces of the matrix and withthe edges of the matrix, which are the sides of the rims. The main sealincludes a seal frame 42 (FIGS. 2 and 3) which is fixed to the walls 31and 32 of the regenerator case and to the bulkhead 23. This seal frameincludes a rear end plate 43 which includes a slightly tapered circularboss 44 that projects through an opening in the rear wall 31. Plate 43is secured to the rear wall by capscrews 46. The frame also includes afront end plate 47 including a boss 48 which projects through a circularopening in the front wall 32. This is secured to the front wall bycapscrews 46. The seal frame 42 also includes three generally parallelstruts or spacers which are fixed to the two end plates. These are anupper support 50 which bolts to the bulkhead 23, a lower support 51which likewise bolts to the bulkhead, and a crossbar or tie bolt 52, theends of which are bolted to the plates 43 and 47. The seal frame thusconstitutes an open framework fixed to the regenerator case andbulkhead.

Within this frame a seal housing which encloses the rollers 34 and 37 or35 and 37, as the case may be. is mounted with slight freedom fortilting movement, generally as described in U.S. Pat. No. 3,384,156, sothat the seal structure accommodates itself to changes in diameter ofthe matrix with temperature and so that the matrix is positivelyimpinged between the opposed rollers on opposite faces of the matrix.The regenerator housing includes parts which seal against the matrix,this being called the primary seal. There is a secondary seal betweenthe matrix housing or primary seal and the seal frame with respect towhich it is slightly movable.

The seal housing 54 (see primarily FIGS. 2, 3, 4, 5, and 8) includes acool face seal bar 55 extending across the outer face of the matrix, abut face seal bar 56 extending across the inner face of the matrix andtwo sideplates 58 which are slightly flexible plates of lnconel(trademark) which are fixed to and join together the seal bars. Theassembly of these four parts thus provides a frame around the matrix 21.The seal housing 54 is mounted for slight tilting movement around anaxis parallel to the axis of rotation of the matrix and the rollers by apivot arm 59 (FIGS. 4 and 8) at each end of the housing, these pivotarms being secured by bolts 60 which pass through the sideplate 58 andinto the end of the cool side seal bar 55.

The seal housing swings on pivots defined by a cylindrical boss 62extending outward from each pivot arm.

Each boss 62 is supported by a spherical bearing 63 in a recess machinedin the inner surface of the end plate 47 or 43. The spherical bearingsallow for some minor dislocations of the supports for this sea] housingassembly. At the rear plate 43, the recess for the spherical bearing isclosed by a plate 64. At the outer wall, an oil manifold 66 (see alsoFIG. 6) bolted onto the boss 48 and a circular cover plate 67 coverthese spherical bearings and provide an inlet for oil. The descriptionof the lubrication system of the seal will be deferred.

The cold side seal bar 55 is of roughly rectangular cross section, asshown most clearly in FIG. 5. The hot side seal bar 56 is split in aplane generally parallel to the surface of the matrix at 72 and includesa cover 68 held to the portion 56 and the upper edge of sideplates 58 bybolts 70. The portions 56 and 68 of the hot side seal bar define betweenthem a chamber 71 of generally circular cross section within which ismounted the roller means 35. The sideplates 58 terminate at the splitline 72 between the two parts of the hot side seal bar and the portion56 of the seal bar is fixed to the sideplate by bolts 70 and 7d.

One of the features of the seal housing 54 is the adaptation todifferential expansion of the cold side seal bar 55 and hot side sealbar 56. Since these, in the particular example are of considerablelength, over 2 feet, and there is a great difference in theirtemperatures when the engine is operating, there is a differentialexpansion of about 0.16 inch between the hot and cold conditions. Toaccommodate this, the hot side seal bar is made about 0.l2 inch shorterthan the cold side seal bar and this difference in length, as well asthe accommodation to relative expansion is taken care of by flexure ofthe lnconel sideplates 58. These are each distorted approximately 0.06inch toward each other at seal bar 56 in the cold condition and warpedapproximately 0.02 inch away from each other when hot, this making upthe total relative expansion of 0.16 inch. By this structure, any sucharrangements as sliding parts are superseded and the structure isconsiderably simplified over what would be required for otherarrangements such as sliding parts or double walls to accommodate theexpansion and preserve the sealing function.

MATRIX-ENGAGING ROLLERS The chamber 71 within the hot side seal bar 56provides an enclosure for the roller means 35 in the lower seal assembly27, which is illustrated in the figures. This roller means includes ahollow shaft 75, the ends of which are supported in spherical rollerbearings 76, one of which is axially fixed in the front end plate 47between the oil manifold 66 and a retainer 78 bolted to the inner sideof plate 47. The bearing 76 at the rear wall 31 is mounted, withclearance for some sliding move ment to accommodate relative thermalgrowth, between retainer 78 and an oil drain cover plate 79, these beingbolted to the rear end plate 43. The retainer 78 bears piston ring seals80 which bear against the cylindrical inner periphery 82 of the ends ofthe portions 56 and 68 of the hot side seal bar. These piston ring sealsprevent leakage to or from the cavity 7! and are radially yielding topermit slight relative motion of the seal housing 54 with respect to theshaft 75.

The hot side matrix roller means 35 includes two rollers 83 preferablyof the contour illustrated clearly in F IG. 3. These rollers are pressedonto the somewhat reduced end portions of shaft 75 and are positivelycoupled to the shaft by face splines at 84. The outer ends of therollers 83 bear piston ring seas 86 which coact with the inner surfaceof retainer 78. The bearings 76 abut the outer ends of the rollers 83and are retained on the shaft respectively by a bolted-on plate 87 andby an oil inlet adapter 88. This mounting of the roller means 35 carriesthe load exerted on the shaft 75 by the matrix directly to the bearings'76 outboard of the matrix and generally in alignment with the plane ofwalls 31 and 32. The bearings being thus located outboard are fartherfrom the extremely hot matrix than would otherwise be the case, which isdesirable from the standpoint of endurance of the hearings. Note thatthese spherical bearings also allow for some wracking or distortion ofthe structure by which the shaft 75 is supported without unduly loadingor harming the bearings.

The shaft '75 and rollers 83 are further protected from heat radiatedfrom the matrix by an insulating jacket defined by thermal insulatingmaterial retained by a thin sheet metal shell or facing. The insulatingmaterial at 90 on the faces of the rollers is retained by rivets 91 andthe insulating material at 92 which covers the shaft 75 between therollers is retained by a thin sheet metal cover, the ends of which abutthe covers of the insulation 90.

The oil inlet adapter 88 which is bolted to the shaft 75 has on itsouter periphery gear teeth 94 which are provided for the purpose ofdriving a matrix rotation sensor (not illustrated) of the type disclosedin US. Pat. No. 3,537,258.

Proceeding now to the arrangement of the cold side roller means 37 whichis directly supported on the cold side seal bar 55; the roller 37 ismounted within an annular recess in the end of the seal bar and issupported both by a radial needletype bearing and by a ball thrustbearing, the former taking the radial loads and the ball bearing theaxial loads. The inner race of ball bearing 95 is held by a washer andnut 96 on a stub shaft 97 projecting into a recess 98 in the seal barfrom the roller 37. The outer race of bearing 95 is held against theshoulder of recess 98 by a retainer ring 100 bolted to the seal bar. Theradial bearing 102 has an inner race held in place against a shoulderwithin recess 98 by a bolted-on cap i103, and the outer race of theradial bearing is retained by a second bolted-on cap 104. This structureprovides for ready installation, removal, and service of the rollers orthe bearings for them. Piston ring seals 106 prevent leakage of oil tothe exterior of the seal bar.

Since the housing 54 on which rollers 37 are mounted can swing about thepivots 62, the rollers can be pressed against the outer surface of thematrix rim 39 and are so pressed by a biasing device 107 including aplunger 108 which bears against a boss 109 on the cool side seal bar 55.The biasing device will not be further described herein but is fullyexplained in the above-mentioned U.S. Pat. No. 3,384,156. The hot sideroller means 34 of the upper seal assembly is similar to that describedbut is positively rotated through a quill shaft PRIMARY SEAL This leadsto a description of the primary seal arrangements for minimizing leakageof air through the interior of seal housing 54 from high pressure to lowpressure. In the structure of this seal, the seal bars 55 and 56 coactdirectly with the matrix, without any removable shoes or facings. Thus,the hot side seal bar 56 has a convex sealing surface 110 (FIGS. 2 and5) and the cool side seal bar 55 has a slightly concave surface 111immediately adjacent the matrix 21. These surfaces lie immediatelyadjacent to labyrinth seal strips (not shown) in the matrix andcooperate with them in known manner.

The cool side seal also includes a guide strip to cooperate with rubbingstrips on the matrix labyrinth seal bars as disclosed in U.S. Pat. No.3,367,405. The structure and mounting of the guide strip in my seal isimproved over that of the patent. As shown most clearly in FIGS. 3 and5, a guide strip 112 is mounted in a slot 113 in the seal bar 55. Itcomprises a wear strip 114 of hard material such as a cemented carbide.The strip is mounted in a holder defined by a carrier 115 and two anglesection pieces 116 bolted to the carrier 115 and which bear against aflange on the wear strip 114. It will be seen that this carrierstructure reinforces and protects the carbide strip, which is relativelybrittle. A spacer 118 lies between the carrier 115 and the bottom ofslot 113. The spacer and carrier are retained in place by two longcapscrews 119 which extend through bores in the hot side seal bar andthrough holes in the spacer 118 into threaded holes in the carrier 115.The spacer 118 may be removed to provide clearance for the thicker endof the guide strip to be removed in the event of need for repair orreplacement. Also, the spacer 118 may act as a shim and by selectiveassembly be used to correct the clearance between the guide strip andthe thickness of the matrix. The wear strip is located between a lug 117on the seal bar and a cap 121 bolted to the carrier 115.

To minimize leakage along the edges of the matrix; that is, the outerfaces of the matrix rims, two side shoes mounted on the inner surface ofa sideplate 58 are biased against each edge of the matrix. Referring toFIGS. 3, 4, 8, and 10, two generally rectangular side shoes in the formof metal plates 120 are located in a recess 122 in each sideplate 58.These shoes closely approach each other at their adjacent edges. Attheir remote edges, each plate has two tangs 123 (FIG. 8) which arereceived in a slot 124 extending from the corner of the recess 122. Theengagement of these tangs in the slots holds the side shoes against theedge of the recess 122 and holds them against the force tending to movethem with the matrix due to friction between the shoe and the face ofthe matrix rim. Each shoe 120 is biased into sliding contact with thematrix by a spring assembly 126 fixed to the outer surface of sideplate58.

Each spring assembly includes a cylinder 127 threaded into the plate 58,a plunger 128 extending through the plate into contact with the centerof the side shoe 120, a compression spring 130, and an abutment 131threaded in the cylinder 127. A thin deformable lock plate holds thecylinders 127 against unscrewing from the plate 58. Note cylinder 127 isclosed by the abutment 131 so that there is no leakage from within therecess 122 to the exterior of plate 58 from which it could bleed to lowpressure. Also, the springs 130 are protected to a considerable extentfrom the heat of the matrix. With the arrangement of side shoesdescribed, the assembly is suitable for movement of the matrix in eitherdirection and the four side shoe assemblies may all be the same.

Since it is contemplated that the regenerator will be used in alocomotive in which case there may be substantial shock loads on theengine in traversing rough track, the seal assemblies 27 include bumperstops which protect the side shoes 120 against possible heavy loads froma shifting matrix. Referring to FIG. 4, a bumper stop 132 is mounted onthe end plate 43 and the end plate 47 adjacent the margin of the boss 44or 48. Each bumper stop includes a head 134 and a hollow stem 135, thestem being swivel mounted in a spherical bearing 136 retained in arecess in the plate by a snapring and held on the stem by a snapring139. A captive compression spring 138 biases the bumper stop to lieperpendicular to the plate, but it can swivel slightly to accommodate toslight coning ofthe rim.

If the stop is engaged by the matrix rim, it stops movement of 7 the rimtoward the end plate before the side shoes bottom in the recesses 122.

BYPASS AND ROLLER CAVITY SEALS The regenerator includes bypass seals ateach rim of the matrix which seal between the matrix and the front andrear walls of the regenerator case. These seals preferably are of thetype described in McCreary U.S. Pat. No. 3,360,275. The bypass seals areinterrupted at the main or bulkhead seal assemblies 27 and someprovision needs to be made in the main seal to prevent flow of gas pastthe outer edge of the matrix. Ends of the bypass seal 140 at the mainseal are illustrated in FIG. 2. A short bypass seal segment 142 (FIGS. 2and 9) mounts on each of the rear and front end plates 43 and 47. Thisis put in place after the seal is installed in the frame 42 and theframe into the regenerator. An angle bracket 143 is bolted to the wall43 or 47. A seal retainer 144 is bolted to the angle bracket. The sealretainer 144 may be adjusted both radially and axially of the matrix byadjustment of the bolts in the holes through which they pass in theangle bracket and seal retainer. A seal block 146 caged within the sealretainer is biased into contact with the inner surface of the matrix rimby leaf springs 147. The seal block is trapped in the directioncircumferentially of the matrix by a channel-shaped member 148 held byscrews 149.

Bypass seals are also provided on the hot side seal (see FIGS. 3 and10). Referring to FIG. 10, an opening 150 in the hot side seal bar 56provides foraccess of the roller 83 to the matrix rim. Two L-shapedcavity shoes 151 float in cor responding L-shaped slots cut in the innerface 110 of the seal bar. These are biased into engagement with theinner surface of the matrix rim by compression spring 152 trapped inrecesses in the seal bar. Between the L-shaped cavity shoes 151 and eachedge of the seal bar, floating shoes 154 are mounted in slots cut in theseal assembly. These are biased into contact with the matrix by trappedcompression springs 155.

MAIN SEAL MOUNTING AND SECONDARY SEALS We may now consider thearrangement by which the seal frame 42 is mounted on the bulkhead 23,and also the secon dary seals which seal between the seal frame 42 andthe seal housing 54 which are capable of slight relative movement.

As pointed out previously, the seal frame 42 includes an upper (hotside) support 50 and a lower (cool side) support 51, these being fixedto the end plates 43 and 47, and being fixed to the bulkhead 23 when theseal frame is assembled into the regenerator. The supports form a partof the arrangement by which the secondary seal is mounted as will beseen. Structurally, the support 51 is quite simple, as there is no greattemperature problem on the cool side. For this reason, only the uppersupport 50 will be described in detail.

The seal support which is on the inside of the matrix, which is theupper support in the lower seal and support assembly described here,faces severe temperature problems. It is exposed to hot exhaust gas fromthe turbine and to radiation from the engine combustion chambers. Also,the seal bar to which it is connected is in contact with the surface ofthe matrix which is quite hot. The seal support is bolted to theregenerator bulkhead which acts as a heat sink and which is cooled tosome extent by the compressor discharge air which flows in contact withthe face of the bulkhead, and is thus substantially cooler than theseal.

It is, of course, quite important that the whole arrangement be asnearly as possible airtight to minimize leakage of the compressed air tothe engine exhaust.

Referring now generally to FIG. 2 and particularly to F IGS. 1 1, 12,and 13, the upper seal support 50 is an assembly which makes provisionfor relative thermal expansion between the seal frame 42 and thebulkhead 23 to which it is fixed. It includes a straight support barwhich has integral with it at each end a head 158. Tapped holes 159 inthe rear face of the support bar receive bolts which pass through thebulkhead and fix it to the bulkhead, such bolts (for the lower Support)being indicated at 160 in FIG. 2. Bolts 161 pass through the end plates43 and 47 and into tapped holes in the outer surface of the heads 158 tofix the seal frame to the bulkhead.

A seal bar 162 is mounted on the support bar 156 by an arrangement whichcenters it in the direction axially of the matrix while allowingrelative expansion between the parts 156 and 162. Bar 156 has ahorizontally projecting flange 163 which is divided into sections by anumber of expansion slots 164. This compensates for the fact that theflange is more highly heated than the body of the bar. The rear edge ofbar 162 is slotted to provide an upper flange 166 and a lower flange 167which fit over and under the flange 163 of the support bar. There is,thus, a tongue and groove connection between these two parts. The sealbar is fixedly located with respect to the support bar at the midpointby a dowel 168 which is a close fit in reamed bores in the flanges 166,163, and 167. Additional locating pins 170 disposed along the structurebetween pin 168 and each head 158 are fitted in holes in the flange 163but are in holes 171 elongated axially of the matrix in the flanges 166and 167 so that relative expansion of the support bar and seal bar arepermitted.

Capscrews 172 which pass with clearance through holes in flanges 166 and163 are threaded into holes in the flange 167. These hold flanges 166and 167 together so that they bear against the flange 163 to limit aleakage path around the flange 163. These flanges also close off ingreat part the leakage path defined by the slots 164 in the support bar156.

A filler strip 174 is mounted below flange 163 and retained in part byan abutment 175 on the support bar. This also serves to block off theslots 164. The filler strip 174 is ultimately retained in place on thesupport bar by a secondary seal retainer 176 (FIG. 2) which is bolted tothe underside of support bar 156. The filler strip 174 is in twosections aligned end to end with a small gap between them at the middle,and each section is located in the direction axially of the matrix by apin 177 at one end. The pin holds the end of the filler strip adjacenthead 158 closely against the end of the slot.

When the engine is assembled, the forward face of the bulk head islagged or insulated to reduce heat transfer to the bulkhead from thecompressed gas and combustion apparatus. Also, the forward face of thesupport bar 156 is covered with insulation. Thus, the temperature of themain body of the support bar, exclusive of the flange 163, and of thebulkhead is determined largely by the exhaust temperature. The seal bar162 becomes considerably hotter but, as pointed out, this may expandrelative to the support bar without departing from its location which isfixed by the pin 168.

The slots 164 in flange 163 allow it to expand without distorting thestructure or setting up undesirable stresses. Likewise, the filler strip174 can expand with respect to the other parts. As will be seen, thisstructure provides for a minimum of thermal stress or distortion whilepositively locating and supporting the main seal.

The secondary seal retainer 176 is a rectangular frame made in two partsso that it can be fitted around the matrix and which is bolted to thesupport bars 50 and 51. Another secondary seal support frame, likewisein two parts, identified as 178, is bolted to the seal housing 54. Thesupport frames define outer and inner grooves to receive the rectangularsecondary seal. The secondary seal 179 is a rectangular frame of thinsheet metal with wires welded to the edges to define a somewhat flexiblestrip bridging the gap between the seal housing and the seal frame. Byslight flexure or slight slippage of this seal in the slots in which itis mounted, the gap between the seal housing and the bulkhead is closedagainst the difference between highand low-pressure sides of theregenerator and the slight rocking movement of the seal housing ispermitted. It will be noted that a portion of this secondary seal whichextends past the edges of the matrix is shown in FIG. 4.

The seal bar 162 bears two projections 180 and is cut away between themto define a keyway 181 at the center plane of the matrix. A lug 183 onthe seal housing 54 enters this keyway to locate the seal housingaxially of the matrix. A similar lug 184 on the cold side of the sealhousing enters a similar keyway in the lower support 51.

Small retainer plates 186 may be tack-welded to the surface of the sealbar 162 opposite to filler strip 174 to prevent any possibility of pin168 dropping out, particularly when the pin is used in the upper seal inwhich position it is inverted with respect to that shown in FIGS. 11 and12.

CIRCULATION OF LUBRICATING AND COOLING OIL Proper circulation of oil tothe bearings of the rotatable structures for lubrication and also withinthe seal housing for cooling'is quite important, particularly since itshould be remembered that in the preferred embodiment the temperature atthe hot side of the matrix is over l,0O0 F. My main seal structureprovides improved arrangements for circulating the oil and also forcoupling the seal to the oil supply and return conduits in theregenerator. In this connection, the structure shown is that of thelower matrix seal and support assembly, but the structure of the uppermatrix seal and support assembly is essentially the same so far as thelubrication is concemed.

Referring first to FIGS. 3, 6, and 7, the oil is fed to oil manifolds 66mounted on the outer front end plate 47 by a pipe (not shown) coupled toan inlet conduit 187. Some of this oil is fed through a bore 188 in anipple 190 which projects into a recess in the oil inlet adapter 88bolted to shaft 75. The junction between these two is sealed by pistonring seals as shown. The oil continues through the central passage inthe oil inlet adapter into the relatively large central bore 191 in thehollow shaft 75. Some of this oil flows outwardly through radialmetering passages 192 and 194 near the ends of the shaft and along thereduced portions of the periphery of the shaft to the spherical bearings76 by way of slots (not shown) in the face of roller 83. An outlet forthe oil which has flowed through bearings 76 is provided at 195 in thelower portion of the oil manifold 66. The oil which is flowed throughthe other spherical bearing 76 flows into the space within oil draincover plate 79 mounted on end plate 43. Also, some oil under pressureflows through a metering hole 196 in plate 87 fixed to the end of shaft75. This metering hole determines the amount of oil which simply flowsthrough the passage 1511, apart from that required for lubrication, tocontribute to the cooling of the hot side roller.

The oil drain from the inner side of the matrix which, in theinstallation referred to, is between the two matrices and relativelyinaccessible, includes an automatic plug-in arrangement by which thereturn oil line couples to a drain line (not illustrated). Thisstructure includes a spring bellows 202 to which are fixed two heads orflanges 203 and 204. Head 203 is bolted over an opening in the lowerpart of oil drain cover plate 79. Flange 204 bears a seal 206 in itsouter face which bears against the structure to which it is connectedand so held by the spring force of the bellows, these bellows alsoserving to take up any changes in dimension. Alignment of the oil drainconnection with the fixed structure of the engine is assured by a pilot207 comprising two crossed plates with tapered outer ends, thusproviding a spider through which the oil can flow freely.

Oil is supplied to lubricate the cool side rollers 37 from manifold 66through pivot 62. A passage 208 in the oil manifold communicates with aspigot 210 which enters a recess 211 in the pivot 62 from which it flowsthrough a series of drilled intercommunicating passages, identified as212 in the pivot arm 59 and 213 in the cool side seal bar 55, into adistributing passage 215 extending from end to end of the cool side sealbar concentric with the axis of rollers 37. This oil flows outwardlythrough metering holes 216 in caps 103 and thus to the needle bearings102. Oil can flow outwardly through small passages 218 in the stub shaft97 to the ball thrust bearing 95, leakage of the oil being prevented byseals 106. The lower portions of the bearing recesses 98 are jointed byan oil drain passage 219 which intersects the downwardly extendingcentral vent passage 220 which communicates through a flexible bellows222 with a line 224 to a sump (not illustrated).

As will be apparent, the structure just described provides for adequatelubrication of the moving parts and for circula tion of some oil forcooling purposes while providing for ready assembly of the seal into theregenerator and coupling of the oil lines.

CONCLUSION it should be clear to those skilled in the art from theforegoing that the seal described and claimed herein represents a numberof significant improvements over prior art devices and is particularlysuited to the requirements of gas turbine regenerator installations.

The detailed description of the preferred embodiment of the inventionfor the purpose of explaining the principles thereof is not to beconsidered as limiting or restricting the invention, as manymodifications may be made by the exercise of skill in the art.

lclaim:

l. A main seal for a rotary regenerator including a case, a bulkhead, arotatable annular radial-flow matrix, and main seals cooperating withthe matrix at the bulkhead; the main seal comprising, in combination, ahousing including a first seal bar extending across the hotter face ofthe matrix, a second seal bar extending across the cooler face of thematrix, and sideplates connecting and rigidly fixed to the seal bars andadapted to extend across the edges of the matrix; the sideplates beingadapted to undergo flexure to accommodate relative thermal expansion ofthe lengths of the seal bars; means connecting the sideplates to thecase so as to support the sideplates from the case and the seal barsfrom the sideplates; and roller means engaging one face of the matrixmounted on the housing and supported by the sideplates.

2. A main seal for a rotary regenerator including a case, a bulkhead, arotatable annular radial-low matrix having hotter and cooler faces, andmain seals cooperating with the matrix at the bulkhead; the main sealcomprising, in combination, a housing including a first seal barextending across the hotter face of the matrix, a second seal barextending across the cooler face of the matrix, and sideplatesconnecting and rigidly fixed to the seal bars and adapted to extendacross the edges of the matrix; the sideplates being supported by thecase and supporting the seal bars and being adapted to undergo flexureto accommodate relative thermal expansion of the lengths of the sealbars; the main seal also including two sets of matrix-engaging rollersengaging the said faces, one set being mounted in each seal bar, one setof rollers being rotatably supported by the case independently of thehousing and the other set of rollers being supported by the sideplates.

3. A main seal for a rotary regenerator including a case, a bulkhead, arotatable annular radial-flow matrix, and main seals cooperating withthe matrix at the bulkhead; the main seal comprising, in combination, ahousing including a first seal bar extending across and in sealingrelation to the hotter face of the matrix, a second seal bar extendingacross and in sealing relation to the cooler face of the matrix, andsideplates connecting and rigidly fixed to the seal bars and extendingacross the edges of the matrix, the seal bars being rigid columnarstructures and the sideplates being adapted to undergo flexure toaccommodate relative thermal expansion of the lengths of the seal bars;the main seal also including two sets of matrix-engaging rollersengaging the hotter and cooler faces of the matrix, respectively, tolocate and support the matrix, one of the said sets of rollers beingsupported by the said housing.

1. A main seal for a rotary regenerator including a case, a bulkhead, arotatable annular radial-flow matrix, and main seals cooperating withthe matrix at the bulkhead; the main seal comprising, in combination, ahousing including a first seal bar extending across the hotter face ofthe matrix, a second seal bar extending across the cooler face of thematrix, and sideplates connecting and rigidly fixed to the seal bars andadapted to extend across the edges of the matrix; the sideplates beingadapted to undergo flexure to accommodate relative thermal expansion ofthe lengths of the seal bars; means connecting the sideplates to thecase so as to support the sideplates from the case and the seal barsfrom the sideplates; and roller means engaging one face of the matrixmounted on the housing and supported by the sideplates.
 2. A main sealfor a rotary regenerator including a case, a bulkhead, a rotatableannular radial-flow matrix having hotter and cooler faces, and mainseals cooperating with the matrix at the bulkhead; the main sealcomprising, in combination, a housing including a first seal barextending across the hotter face of the matrix, a second seal barextending across the cooler face of the matrix, and sideplatesconnecting and rigidly fixed to the seal bars and adapted to extendacross the edges of the matrix; the sideplates being supported by thecase and supporting the seal bars and being adapted to undergo flexureto accommodate relative thermal expansion of the lengths of the sealbars; the main seal also including two sets of matrix-engaging rollersengaging the said faces, one set being mounted in each seal bar, one setof rollers being rotatably supported by the case independently of thehousing and the other set of rollers being supported by the sideplates.3. A main seal for a rotary regenerator including a case, a bulkhead, arotatable annular radial-flow matrix, and main seals cooperating withthe matrix at the bulkhead; the main seal comprising, in combination, ahousing including a first seal bar extending across and in sealingrelation to the hotter face of the matrix, a second seal bar extendingacross and in sealing relation to the cooler face of the matrix, andsideplates connecting and rigidly fixed to the seal bars and extendingacross the edges of the matrix, the seal bars being rigid columnarstructures and the sideplates being adapted to undergo flexure toaccommodate relative thermal expansion of the lengths of the seal bars;the main seal also including two sets of matrix-engaging rollersengaging the hotter and cooler faces of the matrix, respectively, tolocate and support the matrix, one of the said sets of rollers beingsupported by the said housing.